I'm looking to setup high availability with Clustering and Database Mirroring on my SQL 2008 R2 Server with log shipping offsite for Disaster Recovery(Not sure if this is the best way for High availability? What is everyone else using? Third party? Or MS built-in tools?);

Two servers, windows 2008 R2, SQL 2008 R2 Ent. Connected to an EqualLogic iSCSI SAN with 1 SQL server off site connected to Equallogic iSCSI SAN.

Here are my questions;

1. Does the Cluster share a singe IP Address?2. With Database mirroring can you failover and perform maintenance on the primary then fail back when the primary is back online? 3. If you bring the primary down for a day, the database will be out of sync, Can you switch back and forth on the fly?...Do you need the DB's to sync first in order to failback? or can it come on line and still be syncing?? 4. When Mirroring are both Databases online?5. Has anyone had success setting up Database mirroring to an offsite server with Syncronous Saftey mode without affecting performance?6. Has anyone had more downtime with Clustering and Database mirroring then without?

From reading your post it sounds very much like you require AlwaysOn in SQL Server 2012, are you not able to make the upgrade and utilise the newer technology?

Aside that I'll answer what i can

gregtm (7/2/2012)1. Does the Cluster share a singe IP Address?

Yes that's the whole point of clustering resources are shared among nodes although only one can own the resource(s) at a time.

gregtm (7/2/2012)2. With Database mirroring can you failover and perform maintenance on the primary then fail back when the primary is back online?

no, for the same reason as in q4

gregtm (7/2/2012)3. If you bring the primary down for a day, the database will be out of sync, Can you switch back and forth on the fly?...Do you need the DB's to sync first in order to failback? or can it come on line and still be syncing??

[quote]gregtm (7/2/2012)4. When Mirroring are both Databases online?

No, one database is in restoring state as transactions are continuously fed between the 2 endpoints. You can use snapshots if you have Enterprise edition of sql server.

gregtm (7/2/2012)5. Has anyone had success setting up Database mirroring to an offsite server with Syncronous Saftey mode without affecting performance?

Never done it myself, but with synchrounous mirroring over WANs you have to test and get it right otherwise unexpected failovers can occur due to network latency.

I think your answer to number 2 is incomplete. Once the original principal database has caught up, you can failover and 'return' the original principal to being the principal server. We do this every month when we apply Microsoft patches. Fortunately, we have low transaction volume, so the catch-up period is mercifully brief. Can't say what would happen in high volume environment - could end up always playing catchup and never resynchronize?